Patents by Inventor Roger Hugh Piggin

Roger Hugh Piggin has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Photographic high contrast silver halide material
    Patent number: 5736295
    Abstract: A density enhancing amine compound is incorporated into a silver halide element containing both spectrally sensitized and non-spectrally sensitized silver halide grains in the emulsion layer.
    Type: Grant
    Filed: August 8, 1996
    Date of Patent: April 7, 1998
    Assignee: Eastman Kodak Company
    Inventors: Allison Hazel Caroline Dale, Roger Hugh Piggin